//函数
function fn(a:number,b:string="456"):boolean{
 return true
}
function fn2(...arr:string[]){
 let sum:string="";
 for (let i = 0; i < arguments.length; i++) {
    sum+=arguments[i];
    return sum;
 }
}
fn2("a","b")
fn2("a","b","cdsjk","fdkls")
let fn3:(a:string,b:number)=>boolean;
fn3=(x,y)=>{
    return false
}
type fnType=(a:string,b:number)=>boolean;
let fn4:fnType=(x,y)=>{
    return false
}
let fn5:(x:number)=>boolean=(x)=>{
    return false
};

export default{};